Motor spin up with auxiliary power boost

ABSTRACT

An apparatus and associated method that contemplate a data storage disc and a motor supporting the disc in rotation. Control circuitry operates to spin up the disc drive by accelerating the motor to a steady state speed by: beginning the spin up by energizing the motor with a primary power; comparing an amount of auxiliary power that is available from a battery to a predefined threshold; and before the motor is accelerated to the steady state speed and if the threshold comparison is favorable, then boosting the primary power by discharging the battery for a predetermined boost interval.

RELATED APPLICATION

This is a continuation application claiming the benefit of priority toU.S. non-provisional application Ser. No. 14/704,588, which issues asU.S. Pat. No. 10,229,710 on Mar. 12, 2019.

SUMMARY

Some embodiments of the present technology contemplate an apparatushaving a data storage disc and a motor supporting the disc in rotation.Control circuitry operates to spin up the disc drive by accelerating themotor to a steady state speed by: beginning the spin up by energizingthe motor with a primary power; comparing an amount of auxiliary powerthat is available from a battery to a predefined threshold; and beforethe motor is accelerated to the steady state speed and if the thresholdcomparison is favorable, then boosting the primary power by dischargingthe battery for a predetermined boost interval.

Some embodiments of the present technology contemplate an apparatushaving a battery, a data storage disc, and a motor supporting the discin rotation. Control circuitry operates to compare an amount ofauxiliary power that is available from the battery to a predefinedthreshold, and if the threshold comparison is favorable then boost aprimary power to the motor by discharging the battery for apredetermined boost interval.

Some embodiments of this technology contemplate a method characterizedby steps of: obtaining a data storage device having a battery, a datastorage disc, and a motor operably supporting the disc in rotation;accelerating the motor to a predetermined steady state speed; comparingan amount of auxiliary power that is available from the battery to apredefined threshold; and if the comparing step satisfies the thresholdrequirement, then during the accelerating step boosting a primary powerto the motor by discharging the battery.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a plan view of a disc drive data storage device that isconstructed in accordance with embodiments of the present technology.

FIG. 2 depicts a block diagram of the control system in the disc driveof FIG. 1.

FIG. 3 depicts a block diagram of the motor control circuitry in thecontrol system of FIG. 2.

FIG. 4 depicts a block diagram of the power boosting circuitry in thedisc drive of FIG. 1.

FIG. 5 depicts a graphical comparison of a spin up using the boost powerof this technology to a spin up not using the boost power of thistechnology.

FIG. 6 depicts a flowchart of steps in a method for MOTOR SPIN UP inaccordance with embodiments of this technology.

FIG. 7 depicts a block diagram of alternative embodiments of the powerboosting circuitry of FIG. 4.

FIG. 8 depicts a block diagram of alternative embodiments in which thedisc drive of FIG. 1 is included in a storage array within a wide areanetwork computer system.

FIG. 9 depicts a block diagram of the storage array of FIG. 8.

FIG. 10 depicts a block diagram of alternative embodiments in which thepower boost circuitry resides externally to the disc drive.

DETAILED DESCRIPTION

Initially, it is to be appreciated that this disclosure is by way ofexample only, not by limitation. The power concepts herein are notlimited to use or application with any specific system or method. Thus,although the instrumentalities described herein are for the convenienceof explanation, shown and described with respect to exemplaryembodiments, it will be appreciated that the principles herein may beapplied equally in other types of systems and methods involving spinningup an electric motor.

The present disclosure generally relates to the design and control ofelectronic circuitry that is employed to spin up a motor. By “spin up”it is meant the process of starting the motor from rest or from areduced speed and accelerating it to an operational, steady state speed.The interval of time necessary to spin up the motor is referred toherein as the time to ready (TTR). A primary power supply is boosted byinclusion of an auxiliary power to shorten the TTR.

Embodiments of the technology are described herein as practicallyapplied to spinning up a motor in a disc drive data storage device,although the contemplated embodiments are not so limited. In equivalentalternative embodiments the motor can be something other than a discdrive motor. From reading the disclosure herein of the illustrativeembodiments, the skilled artisan does not need an enumeration of alltypes of motor systems that are suited for using this technology inorder to understand the scope of the claimed subject matter, and so nosuch enumeration is attempted.

For purposes of these illustrative embodiments, FIG. 1 provides a topplan view of a data storage device in the form of a disc drive 100 thatis constructed in accordance with illustrative embodiments of thepresent technology. A base deck 102 and a top cover 104 (shown inpartial cutaway) cooperate to form a sealed housing for the disc drive100. A spindle motor 106 rotates one or more magnetic recording discs108. An actuator assembly 110 supports an array of read/write heads 112adjacent the respective disc surfaces. The actuator assembly 110 isrotated through the application of current to a voice coil motor (VCM)116.

The spindle motor 106 in a high capacity disc drive 100 rotates a stackof discs 108. The additional mass of six discs 108, for example,requires more electrical energy to spin up in the same TTR in comparisonto another disc drive 100 having only one disc 108. However, costconstraints and power budgets prevent outright sizing the motor and/orpower supply large enough to equalize the TTR performance of low andhigh capacity disc drives 100. However, reducing the TTR in highcapacity disc drives 100 would be advantageous in providing faster dataaccess to the end-user. It is to technological solutions of that problemthat the embodiments of this technology are directed.

FIG. 2 is a block depiction of relevant portions of a control circuitcontrolling operation of the disc drive 100 of FIG. 1.Position-controlling of the read/write head(s) 112 is provided by aservo control circuit 118 that is programmed with computer code to forma servo control loop. The servo control circuit 118 generally includes acontroller 120, a memory such as the random access memory (RAM) 122depicted, a demodulator (DEMOD) 124, and a motor control circuit 126.Certain details are known to the skilled artisan and thus not depicted.For example, typically the controller 120 can include a general purposeprocessor in conjunction with an application specific integrated circuit(ASIC) hardware-based servo controller.

FIG. 3 is a block depiction of relevant portions of the motor controlcircuitry 126 of FIG. 2. Control logic 128 receives commands from, andoutputs state data to, the controller 120, and controls operation of themotor 106 during transitional operations (referred to as spin up andspin down) and steady-state operations. The control logic 128 includesspin up boost logic 130 that operably decreases the motor 106's spin upcycle time (TTR) in accordance with this technology. Spindle drivercircuitry 132 applies drive currents to the phases of the spindle motor106 over a number of sequential commutation steps to rotate the motor106. During each commutation step, current is applied to one phase, sunkfrom another phase, and a third phase is held at a high impedance in anunenergized state. Back electromagnetic force (bemf) detection circuitry134 measures the bemf generated on the unenergized phase, compares thisvoltage to the voltage at a center tap, and outputs a zero crossing (ZX)signal when the bemf voltage changes polarity with respect to thevoltage at the center tap. A commutation circuit 136 uses the ZX signalsto generate and output commutation timing (CT) signals to time theapplication of the next commutation step.

FIG. 4 is a block depiction more particularly detailing implementationof the reduced TTR of this technology. In these illustrative embodimentsthe components reside within the disc drive 100, interconnected via itsprinted circuit board assembly (PCBA) 138. However, the contemplatedembodiments are not so limited. In alternative embodiments discussedbelow some of the components and circuitry can reside outside the discdrive 100, between it and the external source of power.

A power supply 140 operably receives input alternating current (AC)power from the source of power (not shown) and outputs variousassociated direct current (DC) voltages on different supply paths, suchas the path 142. For the sake of an illustrative description entirely,without limitation, the output voltage from the power supply 140, hereinreferred to as the “supply power,” can be provided at a nominal valuesuch as twelve volts (12V). This supply power is supplied throughprotection diode 143 to a regulator 144 which applies voltage regulationto provide an output regulated voltage to path 146. The regulatedvoltage passes to the motor 106, a ground connection 148 denoting thecompletion of this primary supply power loop. An analog to digitalconverter (“ADC”) 150 provides to the spin up boost logic 130 a digitalindication of the supply power. For example, without limitation, the ADC150 can include an ammeter informing the spin up boost logic 130 of theamount of current supplied to the motor 106.

A recharge circuit 152 receives input voltage from the power supply 140via path 154 to selectively apply recharging current to a rechargeablebattery 156, via path 158. For purposes of this description and meaningof the claims, a “rechargeable battery” or “battery” herein means a typeof electrical battery that stores energy through a reversibleelectrochemical reaction and can be electrically charged, discharged toan electrical load, and then recharged, many times over. Severaldifferent combinations of electrode materials and electrolytes aresuitable for constructing the rechargeable battery in this technology,including but not limited to at least nickel metal hydride, lithium ion,lithium ion polymer, and the like. The battery 156 is selectively usedto supplement the primary power to the motor 106 with an auxiliary powerboost for a predetermined time during spin up of the motor 106.

The battery 156 supplies the auxiliary power on path 160. Another ADC162 provides to the spin up boost logic 130 a digital indication of theavailable auxiliary power (depending on the present charge state of thebattery 156). For example, without limitation, the ADC 162 can includean ammeter informing the spin up boost logic 130 of the amount ofcurrent that is discharged from the battery 156. During normaloperation, path 160 is preferably decoupled from path 142 (i.e., spin upboost logic 130 opens switching element 164) so that the regulator 144receives power from only the power supply 140. The switching element 164can be constructed of a suitable transistor, one or more protectiondiodes, etc., as desired.

FIG. 5 graphically depicts a typical spin up velocity curve 166 for themotor 106, from a zero velocity at time t₀ to a steady state velocity attime t_(TTR) (“Time to Ready”). The curve 166 has an initial trajectoryduring open loop acceleration from t₀ to an intermediate velocity V_(I)at time t_(I), and then another trajectory during closed loopacceleration from t_(I) to the t_(TTR). Both trajectories in theseillustrative embodiments are linear, although the contemplatedembodiments are not so limited in that they can be partially or entirelynonlinear.

FIG. 6 depicts a graphical comparison of a spin up velocity curve 168 ofthis technology to a spin up velocity curve 166 of disc drive not usingthe boost power of this technology. The velocity curves are plotted froma zero velocity at time t₀ to a steady state velocity at time t_(TTR)(“time to ready”). The curves 166, 168 have an initial trajectory duringopen loop acceleration from t_(I) to an intermediate velocity V_(I) attime t₁. In these illustrative embodiments the curves 166, 168 havedifferent trajectories during closed loop acceleration from t_(I) to thecorresponding t_(TTR). Both trajectories in these illustrativeembodiments are linear, although the contemplated embodiments are not solimited in that they can be partially or entirely nonlinear.

Curve 168 depicts at time t_(I) the spin up boost logic 130 (FIG. 4) canclose the switching element 164 to boost the power from the power supply140 by the inclusion of the auxiliary power from the battery 156. Theincreased trajectory of the curve 168 results in a significantly reducedtime required to reach the V_(TTR). In alternative embodiments (notdepicted) the spin up boost logic 130 can close the switching element164 at time t₀ to boost the power to the motor 106 substantiallysimultaneously to the initial open loop acceleration of the motor 106.

FIG. 6 is a flowchart depicting steps in a method 200 for MOTOR SPIN UPperformed by computer execution of boost spin up logic (such as 130) inaccordance with illustrative embodiments of the present invention. Themethod begins in block 202 with the controller (such as 120 depicted inFIG. 2) detecting a device enable (“EN”) signal from the host device.The EN signal is employed in these illustrative embodiments to spin upthe motor (such as 106) to the steady state speed, at a time when thepower to the motor has been reduced or shut off during reduced activityor inactivity.

In block 204 the spin up boost logic determines whether the battery(such as 156) is presently storing enough power to provide the boost ofstart up power needed to significantly reduce the TTR. For example,without limitation, during reduction to practice it was empiricallydetermined that reducing the TTR required boosting the supply power withan auxiliary power (from the battery) of two amperes at twelve volts andfor eight seconds. The energy required from the auxiliary power is:E=2 amps*12 volts*8 seconds=53mAh

If the battery has been used repeatedly in numerous spin up cycles andnot yet recharged, then the determination of block 204 can be “no.” Inthat case, control passes to block 206 where the disc drive 100 spins upthe motor with only the primary supply power, forgoing the reduced TTRbenefits of this technology. If, contrarily, the determination of block206 is “yes,” then in block 208 the spin up boost logic computes a boostinterval during which the switching element 164 is to be closed in orderto provide the desired boost during the spin up. In some embodiments theboost interval can be a predetermined interval of elapsed time. Forexample, the spin up boost logic can define the interval as beginning atthe intermediate interval of time t_(I) and last for a duration of theeight seconds used in the example above. Alternatively, the spin upboost logic can define the boost interval in terms of a voltage dropfrom an initial voltage of the battery at the beginning of the intervalto a predetermined reduced voltage.

After the boost interval is predefined, and at the beginning of thepredefined boost interval, in block 210 the spin up boost logic closesthe switching element to begin boosting the spin up power. In block 212it is determined whether the boost interval is completed. If thedetermination of block 212 is “yes,” then in block 214 the spin up boostlogic opens the switching element to end boosting the spin up power.

In block 216 it is determined whether to recharge the battery or not.First, that determination is delayed until a predetermined time haselapsed after the switching element is opened in block 214. For example,the spin up boost logic can proceed in response to a timer that isstarted in conjunction with actuation of the switching element in block210. The timer can start with the closing of the switching element atthe beginning of the boosting, or the timer can start with the openingof the switching element at the end of the boosting. For anotherexample, the spin up boost logic can proceed in response to the power(in terms of current) to the motor dropping below a predetermined valueafter the boosting is ended. In either case, the momentary delay beforerecharging, when recharging occurs, ensures not overloading the externalpower supply by the boosting and recharging duties.

After the delay, the spin up boost logic then determines if the batteryhas been sufficiently discharged to warrant a call to the rechargecircuit (such as 152) to begin recharging the battery to a maximumpower. That determination can be based on a comparison of the battery'sstored energy to a preselected threshold value, such as 80% of batterycapacity. If the determination of block 216 is “yes,” then the batteryis recharged to completion in blocks 218, 220.

The embodiments depicted in FIG. 4 describe only one 12V power channelfor powering the high voltage components, such as the motor 106,although the contemplated embodiments are not so limited. FIG. 7 depictsalternative embodiments in which the disc drive 100 also has a reducedvoltage (such as 5V) power channel for powering low voltage components,such as the control electronics. In a similar fashion described above,the battery and associated circuitry is configured to share thebattery's auxiliary power with each of the power channels.Alternatively, each power channel can be provided with a dedicatedbattery. The spin up boost logic 130 individually controls a switchingelement for each power channel so that boosting the primary power in oneof the power channels can be done independently of boosting the primarypower in the other power channel.

Furthermore, although the illustrative embodiments emphasize the use ofprimary and auxiliary power to energize just the motor 106, thecontemplated embodiments are not so limited. The embodiments of thistechnology contemplate circuitries providing the primary and auxiliarypower to service the entire electrical requirements (high voltage andlow voltage requirements) of the disc drive 100.

The embodiments discussed so far are related to the battery andassociated circuitry residing within the disc drive 100; in alternativeembodiments they can reside outside the disc drive 100. For example,FIG. 8 depicts pluralities of the disc drives 100 employed to formstorage arrays 222 _(A), 222 _(B) in a computer-based system 224characterized as a wide area network (WAN). The system 224 includes anumber of host computers 226, respectively identified as hosts A, B andC. The host computers 226 interact with each other as well as with thedata storage arrays 222 _(A), 222 _(B) via a fabric 228. The fabric 228is preferably characterized as a fibre-channel based switching network,although other configurations can be utilized as well including theInternet. It is contemplated that the host computer 226 _(A) and thedata storage array 222 _(A) are physically located at a first site, thehost computer 226 _(B) and the storage array 222 _(B) are physicallylocated at a second site, and the host computer 226 _(C) is at yet athird site, although such is merely illustrative and not limiting.

As shown in FIG. 9, the storage array 222 _(A) can include a pair ofcontrollers 228 _(A1), 228 _(A2) and an array of the data storagedevices 100. The controllers 228 and data storage devices 100 preferablyutilize a fault tolerant arrangement so that the various controllers 228utilize parallel, redundant links and at least some of the user datastored by the system 222 is mirrored, either within the same storagearray 222 or distributed among different storage arrays 222. Each array222 further includes a pair of power modules 230 _(A1), 230 _(A2) thatsupply electrical power to the controllers 228 and the data storagedevices 100. The power modules 230 are preferably configured to operatein tandem so that during normal operation the power module 230 _(A1)supplies power to the controller 228 _(A1) and to half of the datastorage devices 100, and the power module 230 _(A2) supplies power tothe controller 228 _(A2) and to the other half of the data storagedevices 100. Each power module 230 can further be sized and configuredto be able to individually supply all of the power for the array 222should the other power module 230 become inoperative. FIG. 10 depictsrelevant portions of one of the power modules 230 of FIG. 10 inaccordance with these alternative embodiments of the present invention.The components in the power module 230 are similar to the embodiments ofFIG. 4 described above, and as such retain like reference numbers herewhere they reside outside the disc drive 100 between it and the externalsource of supply power (not depicted).

In yet other embodiments of this technology the components in FIG. 10(battery, recharging module, circuitry) can be constructed to reside ina portable module that is removably pluggable into a device. Forexample, without limitation, the portable module can be pluggable into acommunications port in the power module 230, in the disc drive 100, orin the interconnecting power cabling and/or adapter between the powermodule 230 and the disc drive 100. For example, the portable module canprovide the boosted TTR advantages of this technology to an existingproduct by plugging into the system by the product's universal serialbus (USB) port.

It is to be understood that even though numerous characteristics andadvantages of various embodiments of the present invention have been setforth in the foregoing description, together with details of thestructure and function of various embodiments of the invention, thisdetailed description is illustrative only, and changes may be made indetail, especially in matters of structure and arrangements of partswithin the principles of the present invention to the full extentindicated by the broad general meaning of the terms in which theappended claims are expressed. In addition, although the embodimentsdescribed herein are directed to data storage devices, it will beappreciated by those skilled in the art that the claimed subject matteris not so limited and various other systems that spin up a motor canutilize the embodiments of this technology without departing from thespirit and scope of the claimed invention.

What is claimed:
 1. An apparatus, comprising: a disc drive having a datastorage disc; and a motor supporting the disc in rotation; controlcircuitry operable to spin up the disc drive by accelerating the motorto a steady state speed by: beginning the spin up by energizing themotor with only a primary power which relates to a correspondingnon-boosted spin up time to ready (“TTR”) interval of time necessary forthe motor to accelerate to the steady state speed; before the motor isaccelerated to the steady state speed, comparing an amount of auxiliarypower that is available from a battery to a predefined amount ofauxiliary power that, when used to boost the primary power, relates to acorresponding boosted spin up TTR interval of time that is less than thenon-boosted TTR; and before the motor is accelerated to the steady statespeed and if the battery has at least the predefined amount auxiliarypower corresponding to the boosted spin up TTR that is less than thenon-boosted TTR, then boosting the primary power by discharging thebattery for a predetermined boost interval.
 2. The apparatus of claim 1further comprising spin up boost logic computer instructions configuredto control the control circuitry and residing in the disc drive.
 3. Theapparatus of claim 1 2 comprising a plurality of disc drives containedin a storage array.
 4. The apparatus of claim 3 further comprising spinup boost logic computer instructions configured to control the controlcircuitry and residing in the storage array externally to the pluralityof disc drives.
 5. The apparatus of claim 4 further comprising anammeter that informs the controller of the amount of current that isdischarged from the battery.
 6. An apparatus, comprising: a battery; adata storage disc; a motor supporting the disc in rotation; and controlcircuitry operable to compare an amount of auxiliary power that isavailable from the battery to a predefined amount of auxiliary powerthat, when used to boost a primary power to the motor, relates to acorresponding boosted TTR interval of time that is less than anon-boosted TTR interval of time corresponding to energizing the motorwith only the primary power, and if the battery has at least thepredefined amount of auxiliary power corresponding to the boosted TTRthat is less than the non-boosted TTR then boost the primary power tothe motor by discharging the battery for a predetermined boost interval.7. The apparatus of claim 6 wherein the battery and the controlcircuitry reside in a portable module that is removably pluggable into acommunications port of a device selected from the group consisting of adisc drive, an external power module, and a power transmission devicebetween the disc drive and the external power module.
 8. The apparatusof claim 6 further comprising a charger for selectively recharging thedischarged battery.
 9. The apparatus of claim 6 wherein the controlcircuitry comprises a processor-based controller configured to activatea switching element to combine the primary power and the battery power.10. The apparatus of claim 9 wherein the controller activates theswitching element to decouple the battery power from the primary powerduring at least a portion of the spin up.
 11. The apparatus of claim 9wherein the controller activates the switching element to decouple thebattery power from the primary power when the primary power is removedfrom the motor.
 12. The apparatus of claim 6 wherein the controlcircuitry comprises a plurality of power channels and is operable toindividually boost a power to each of the power channels.
 13. Theapparatus of claim 12 wherein the apparatus is a disc drive and thepower channels collectively supply the entire electrical requirementsfor the disc drive.
 14. A method, comprising: obtaining a data storagedevice having a battery, a data storage disc, and a motor operablysupporting the disc in rotation; beginning to accelerate the motor to apredetermined steady state speed by energizing the motor with only aprimary power which relates to a corresponding non-boosted spin up timeto ready (“TTR”) interval of time necessary for the motor to accelerateto the steady state speed; comparing an amount of auxiliary power thatis available from the battery to a predefined amount of auxiliary powerthat, when used to boost the primary power, relates to a correspondingboosted spin up TTR that is less than the non-boosted TTR; and if thecomparing step indicates the battery has at least the predefined amountof auxiliary power corresponding to the boosted spin up TTR that is lessthan the non-boosted TTR, then during the accelerating step boosting theprimary power to the motor by discharging the battery.
 15. The method ofclaim 14 wherein the battery is a rechargeable battery and furthercomprising charging the battery after the boosting step.
 16. The methodof claim 15 wherein the charging step comprises delaying the chargingstep after the boosting step is completed for a predetermined intervalof time.
 17. The method of claim 14 wherein the accelerating step andthe boosting step begin simultaneously.
 18. The method of claim 14wherein the boosting step comprises discharging the battery in relationto a predetermined value of an operational parameter.
 19. The method ofclaim 18 wherein the boosting step comprises discharging the battery inrelation to a predetermined elapsed time.
 20. The method of claim 18wherein the boosting step comprises discharging the battery in relationto a predetermined voltage drop of the battery.